The Patterns of Care Study (PCS) in radiation oncology has the overall goal of improving the care received by cancer patients throughout the USA. To achieve this goal, national surveys will determine structure, process, and outcome of care, emphasizing practice setting, new technologies, and other factors likely to influence outcome. The proposed studies will include cancer of the breast prostate, and lung, which have the highest incidence and death rates in both men and women. This first PCS survey of lung cancer is timely, because positive clinical trials have created the foundation for improvement in treatment and outcome. Cancer of the cervix and esophagus, where radiation therapy is critical and further improvement in care is still needed, will also be studied. Additional outcome data will be collected for other existing studies. A special study will focus on patients treated with implants for prostate cancer. Another special study will focus on the care received by implants in minority-rich facilities. A continuing important collaboration between the American College of Radiology (ACR) and the American College of Surgeons (ACoS) will compare the patterns of treatment for breast cancer patients with locally advanced disease to treatment used in recently reported positive clinical trials. The ongoing close collaboration with national clinical trial groups, especially the Radiation Therapy Oncology Group, enables the PCS to measure the penetration of positive phase III clinical trials into the national practice. Similarly, collaboration with professional organizations provides a foundation for measuring the penetration of evidence-based practice standards and guidelines. An international collaboration will lead to comparison of the processes and outcomes of care for patients with cancer of the breast, cervix, esophagus, and lung between the USA and Japan. For cervix cancer comparisons will also be made with Canada. The PCS findings will direct the development of specific educational programs targeted at correcting identified deficits in care. The research time is experienced and have over twenty-five years of successful Patterns of Care Studies with stable leadership by the Principal Investigator, Director, and sponsoring organization. Ready access to patient records has resulted from the enthusiastic cooperation of the specialty of radiation oncology.